Isn't the Demon Ruins like that too, before lowering the lava? I also think you can't get invaded or summon unless you also have the lord vessel. I've gone down there a number of times without it to get the embers (with the yellow fog still up) and never see summon signs or get invaded. Kirk doesn't even invade.

_________________"They can be a great people, Solaire, they wish to be. They only lack the light to show the way. For this reason above all, their capacity for good, I have sent them you... my only son."